A little unsure of the following instructions for doing the sleeves. First time doing a sweater.

There is a pattern worked over 4 rows. Then it says, Repeat rows 1-4 for pattern, I understand that) at the same time increase 1 st at each end of 5th and every following 4th row (10 times for my size) bringing increased sts into pattern.

I understand I will increase on the 5th row (which will actually be row 1 of the pattern) but it says at each end of 5th and every following 4th, does that mean in the beginning and end of the row or just be sure I do that at the end of each increase row?

Also, if I understand this correctly, the increases will be row 1 of the pattern each time since every 4th row after the 5th will be starting row 1 again of the pattern?